Currently, research and development relating to fourth-generation mobile communication systems is being carried out, and transmission methods for implementing high-speed, high-capacity data transmission are being investigated. One of these transmission methods is OFDM transmission. With regard to OFDM transmission, a technique is known that reduces the amount of computational processing for calculating a weight for each subcarrier when an OFDM signal is received by a smart antenna (adaptive array antenna) (see Patent Document 1, for example).
In the technique described in Patent Document 1, weight generation per subcarrier is avoided, and the associated amount of computational processing reduced, by grouping together a plurality of subcarriers and using the same weight for all the subcarriers in that subcarrier group.
FIG. 1 shows an overview of a radio communication system that uses the technique described in Patent Document 1. In the radio communication system shown in FIG. 1, a transmitting apparatus and a receiving apparatus each equipped with a smart antenna both set one group by gathering together a plurality of adjacent subcarriers in an OFDM signal, and transmit/receive an OFDM signal weighted using weights Wr′0 through Wr′m−1 for individual subcarrier groups.    Patent Document 1: Japanese Patent Application Laid-Open No. 2002-198878